Variable star observations with automatic telescopes

Small automatic telescopes have been used for several years to make wide band, differential photometric observations of brighter variable stars. For example, a single automatic telescope located in Arizona has been used to study essentially the entire class of RS Canum Venaticorum binaries. These stars have changing spot structures that require once-a-night photometric observations - an ideal job for an automatic telescope located in the clear skies of Arizona. The operation of such automatic systems has become so routine that an “Automatic Photoelectric Telescope Service” now makes photometric observations for any institution so requesting. A list of stars is sent to the Arizona site of this service, and every three months the observational results are returned, with the cost typically being similar to the publication page charges. Currently the use of automatic telescopes is being extended to fainter stars and narrower bandwidths. For instance, a highly specialized one-meter telescope has been designed for automatic observations of Ca II K-line emissions from brighter active chromosphere stars. Further extensions of such automation seem likely.

Late-Type Ca II Emission-Line Stars in the Southern Hemisphere

ABSTRACTThe results of a photometric and spectroscopic study of twenty-three late-type southern stars with strong Ca II H and K emission are presented.The presence of photometric variability, with similar properties to the photometric wave phenomenon seen in the RS Canum Venaticorum binaries, is noted in thirteen of the fifteen stars for which extensive photometry was obtained. Of twenty stars for which high resolution radial velocity measurements were obtained, ten are found to be single-lined and seven are found to be double-lined spectroscopic binaries. The periods range from 0.66 up to 53-9 days.